Centrifugal machine for making conical hollow bodies, particularly reenforced concrete poles



Jan. 3, 1933. M. STUHLER 1,392,315

CENTRIFUGAL MACHINE FOR MAKING CONICAL HOLLOW BODIES,

PARTICULARLY REENFORCED CONCRETE POLES Filed Sept. 4, 1931 2 Sheets-Sheet 1 lnven far-.-

' M. s'rUHL'ER Jan. 3, 1933;

' CENTRIFUGAL MACHINE FOR MAKING CONICAL HOLLOW BODI PARTICULARLY REENFORCED CONCRETE POLES Filed Sept. 4, 1951 2 Sheets-Sheet 2 Patented Jan. 3, 1933 UNITED STATES PATENT OFFICE MARTIN s'ri'rHLEn, or COLOGNE, GERMANY CENTBIFUGAL MACHINE FOR MAKING 'CONICAL HOLLOW BODIES, PARTICULARLY REENFORCED CONCRETE POLES Application filed September 4, 1931, Serial No. 561,181, and. in Germany September 26, 1930.

The present invention relates to a centrifugal machine for making conical hollow bodies, particularly reenforced concrete poles.

Conical hollow bodies of this type were hitherto chiefly produced bymachines oft'he lathe system if the centrifugal process was applied. The operation of such machines is, however, quite bothersome and involves serious drawbacks besides requiring much time.

The axial introduction and removal of the molding box is particularly inconvenient and disadvantageous, since it makes it necessary to keep the working space twice as long as the machine. Other defects rendering the 5 application of the centrifugal process in connection with such machines diflicult and expensive are the centering ofthe molding box at :all supporting points, the troublesome rearrangement of'the machineand'the displacement'of the carrying rolls at each variation in the length of the molding boxes,.the unavoidable readjustment of the carrying rolls required for supporting the rotating molding box at every change in diameter, andthe '3 harmful torsion of the molding box.

Another centrifugal machine with rolls known to'the art produces conical hollow bodies by disposing the conical molding box in a cylindrical container carried and driven 3 by two cylindrical rollers. As :a separate cylinder is needed for each box size,the plant becomes too expensive and unsuited for producing a larger number of different types of conical hollow bodies.

The object of the invention is to provide a centrifugal machine with rolls eliminating the 'defectsof the known machines and .methods and constructed so that large and small, 40 long andshort molding boxes may be fed into it andcentrifuged in :any rotation and without any auxiliary equipment :and' special adjustment and therefore without any loss of time, which means aconsiderable saving in material, power, time and labor.

' The invention isbased onthe mathematical theorem that cones-coinciding with the vertex and a line .of the convex surface will rotate 'on one another under the action of rotary forces while the angles of summit of the the roll gear.

cones may difl'er'at will and be acute or obtuse or even of The machine according to the invention comprises two truncated cones disposed side by side in a horizontal plane and driven at exactly the same angular velocity, the virtual ver-tices of the cones coinciding in a common point. The molding boxes for the conical hollow bodies to be centrifuged are conical also and are placed on the roll gear formed by the two truncated cones in such a way that their virtual vertices coincide also with the common summit point of the cones forming If the truncated cones are driven in the same direction and at the same angular velocity, the molding box resting on the truncated cones will be rotated in the opposite direction.

The centrifugal machine has preferably a length capable of handling even the largest poles, and the dimensions are chosen so as -tO-LCOVBI' the current shapes of usual conicity.

another, with their circumference forming part of a convex surface. On these driving .85 discs the molding box is placed with guide rings disposed at corresponding distances and having a suitable profile to prevent slipping of the rotating box. The driving discs of the roll gear can be fitted with solid or pneumatic rubber tires, pads or packing-s.

Byway of example, one form of the invention is illustrated in the accompanying drawings, in which Figure 1 is a diagram showing the principle of the machine according to the invention seen from above; Fig. 2, a front View of the machine; Fig. 3, a side view-seen from the left-hand side of Fig. 2; Fig. 4,

atop view of the machine withouta molding box; Fig. .5, a longitudinal section of a mold- .100

ing box; Fig. 6, a longitudinal section of another molding box; and Fig. 7, a diagrammatic side view of the machine with molding boxes of difierent diameter.

As Fig. 1 shows, the principle of the invention is represented by the three cones Z), 0 and d coinciding with their vertices in the common point a and contacting only in two lines of their convex surfaces. The upper cone (5 serves as molding box and is carried and driven by the two other rotatably arranged cones b and 0, each of which contacts with it in one convex surface line. In this manner a device is provided equalling in simplicity the known roll gear for producing cylindrical concrete pipes.

In the construction shown in Figs. 2 to 6, the truncated cones b and c of the roll gear are formed by the driving discs 0 equidistantly disposed on the shafts f which are rotatably arranged on the brackets g in the bearings h. The shafts f carry at their ends the gear wheels 2' which are positively connected and rotated in the same direction by a third toothed wheel Z driven from the pulley 7a. The shafts f can be driven directly by belts, in which case the gear wheels 6 and Z serve only for insuring equal angular velocity for both shafts. Sometimes the drive of only one shaft f may suffice.

According to Fig. 5, the hollow molding box m has the shape of a truncated cone and is provided at equal distances corresponding to the relative spacing of the driving discs 0 with the guide rings n having suitable ex ternal profiles 0 which embrace the circumference of the driving disc e when the molding box is placed on the roll gear, thus imparting rotation to the molding box while maintaining the accurate distance from the common summit point a. The guide rings 1?. serve also for connecting the two halves of the molding box and consist therefore of two parts connected by suitable means.

As Fig. 6 shows, the molding box m need not necessarily possess the pitch of the theoretical cone (Z, it being sufficient if the convex surface passing through the profiles 0 discloses this pitch. The molding box itself may form a cone with a more obtuse or acute angle (Fig. 6), or a cylinder, in which case the rings 1% and the profiles 0 will be connected by the radial webs p. This case has been assumed also in Figs. 2 and 3.

As shown diagrammatically in Fig. 7, molding box cones 11, r2, T3 of any size may be placed on the machine, provided the theoretical vertices of these cones coincide with the common point a of the roll gear.

The machine according to the invention, compared with the existing kinds of centrifugal machines, is very simple and cheap. The molding boxes, too. can be produced with a minimum consumption of material, since the fundamental conical shape is possible not only for the article to be made but for the molding box also. The operation of the machine is quite simple, as no adjustments are needed, so that centrifuging work can be carried on almost uninterruptedly whereby complete utilization of the machine is insured.

The guide rings of the molding boxes may be dispensed with and the driving discs may directly engage the molding box if at least one guide is arovidod to render the molding box non-displaceable. By changing the shafts, bearings and driving discs the ma chine may be adjusted also to other common points in which the vertices coincide, and the plane in which the bearings are disposed may be inclined at will.

I claim z- 1. In a centrifugal machine for making conical hollow bodies, particularly reenforced concrete poles, the combination of two cones arranged in a horizontal plane and driven in the same direction at equal circumferential speed, the vertices of the said cones coinciding in a common point, and a third cone serving as centrifugal molding box and lying on the said con s while touching them each in one line, the said third cone coinciding with its vertex in the same point as the first two cones and being rotated by the driven cones in a direction opposite to the direction of the said driven cones.

2. In a centrifugal machine according to claim 1 two driven cones acting as rollers and a conical molding box, the said conical box and rollers forming truncated cones whose imaginary vertices coincide all in one point. I

3. In a machine according to claim 1 two truncated cones acting as roll gear and reduced to form driving discs, a driving shaft on which the said discs are equidistantly arranged, and a conical molding box carried by the said discs, the peripheries of the said discs being located in the convex surface of the theoretical cone.

4. In a machine according to claim 1 two truncated cones acting as roll gear and reduced to form driving discs, means for driv ing the said discs, the said discs being arranged equidistantly on the said driving means, a conical molding box, guide rings arranged on the molding box and spaced according to the distances between the discs, and an external profile for the said rings adapted to embrace the edge of the said discs and to transmit drive to the molding box.

5. In a machine according to claim 1 two truncated cones acting as roll gear and re duced to form driving discs, means for driving the said discs, the said discs being arranged equidistantly on the said driving means, guide rings arranged on the molding box and spaced according to the distances between the said discs. external profiles for the said rings adapted to embrace the edge of the said discs and to transmit drive to the molding box, the form of the molding box being independent of the form of the theoretical cone, and Webs connecting the profiles falling Within the convex surface of the theoretical cone with the guide rings of the molding box if the molding box; forms a more obtuse or acute angle than the theoretical cone or a cylinder.

6. In a machine according to claim 1 a base plate, bearings firmly supported on the said plate two truncated driven cone rolls reduced to driving discs, shafts carrying the said discs, conical gear Wheels disposed at the 5 ends of the said shafts, and a bevel gear engaging the two gear Wheels and driving them.

7 In a machine according to claim 1 two truncated cones acting as roll gear and reduced to form driving discs, and solid rubber 29 tires for the said driving discs.

8. In a machine according to claim 1 two truncated cones acting as roll gear and reduced to form driving discs, and pneumatic tires for the said discs.

MARTIN sTUi-ILER. 

